In Long Term Evolution Advanced (LTE-A) wireless networks, a radio frame includes a special subframe to transition from a downlink subframe to an uplink subframe. The special subframe includes a downlink pilot time slot (DwPTS) and an uplink pilot time slot (UpPTS) separated by a guard period. The special subframe may have one of a plurality of configurations. However, in some configurations, no demodulation reference signals (DM-RS) are assigned in the DwPTS of the special subframe.